This invention relates generally to an active perfusion balloon catheter, particularly, a catheter having a magnetically driven impeller to facilitate blood flow. Active perfusion balloon catheters may be used in percutaneous transluminal coronary angioplasty and in other medical procedures to maintain blood flow through body lumens.
The need for active perfusion catheters has become more desirable with advances in micro-surgery, neuro-surgery, interventional neuroradiology, minimally invasive coronary arterial bypass procedures, intravascular radiation for prevention of restenosis after angioplasty and stenting, and conventional angioplasty procedures.
Various perfusion catheters are known in the art including WO 95/28983; and U.S. Pat. Nos. 4,581,017; 4,909,252; 4,944,745; 5,092,844; 5,163,910; 5,370,617; 5,405,383; and 5,501,667. Various catheters are disclosed in U.S. Pat. Nos. B1 4,762,129; 5,002,531; and 5,232,445. Magnets, magnetic coupling forces, and pump systems are disclosed in U.S. Pat. Nos. 4,207,485; 4,382,245; 4,569,641; 4,717,315; 5,248,245; 5,253,986; 5,609,602; 5,377,816; 5,456,134; 5,589,721; and 5,501,582. A magnetically coupled implantable medical device is disclosed in WO 95/29716.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties for all purposes.
Accordingly, there is a need for catheters having perfusion to maintain blood flow through body lumens during medical procedures. The active perfusion catheter of the present invention incorporates a magnetically driven impeller that advantageously provides blood flow to coronary arteries temporarily blocked during balloon dilatation. The catheter shafts and components are made of plastics, polymers, or metals known in the art.
The catheter has one or more passages for blood to reach the opposite side of the treatment area during balloon dilatation. Blood flow may be through an active perfusion lumen where aperture holes and a miniature impeller having magnetic coupling properties actively facilitate fluid movement. Impeller rotation is implemented by an external magnetic force. The external magnetic drive system rotates and causes a corresponding rotation of the impeller disposed in the catheter. The impeller may be disposed on a shaft and rotate on bearings to minimize frictional forces.
Blood may also flow through a passive perfusion lumen where aperture holes and system pressure allows blood to flow through the guidewire lumen to regions proximal or distal of the balloon. Passive perfusion may occur through a guidewire lumen as blood enters through one or more apertures in the wall of the shaft. The apertures are located proximal of the balloon, and system pressure drives blood longitudinally through additional perfusion openings or apertures. The active and passive perfusion systems may be used in combination.
The external magnetic drive system may be contained in an enclosure and include an electrical or battery power source. The enclosure provides containment and protection of the drive system and may be placed on the patients body adjacent an area in the body where the impeller of the catheter is disposed.
The drive system includes a magnet or magnetic surface which rotates about an axis. The drive system may be powered by a motor and include an on-off switch, variable speed control, and various control systems to measure and monitor the rotation of the magnetic surface and the corresponding blood flow through the catheter. Also, controls may measure the strength of the magnetic coupling of the magnetic surfaces, and the rotational speed of the impeller. The magnetic drive system includes magnetic flux properties capable of transmitting sufficient magnetic forces to the magnetic impeller and for magnetic coupling to occur.
The impeller may be located in a portion of the catheter intended to be disposed in the ascending aorta which generally allows the catheter to have a larger impeller. Accordingly, the impeller is preferably located about six inches proximal of the balloon.
In sum, the invention relates to a perfusion balloon catheter including a first shaft having proximal and distal portions, a wall, one or more first apertures through the wall, a balloon disposed on the shaft distal of the first apertures, an inflation lumen in communication with the balloon, and a perfusion lumen in communication with the first apertures. At least one impeller is disposed in the perfusion lumen. The impeller has a predetermined shape and one or more magnets disposed thereon. The magnets magnetically couple with a magnetic source causing rotation of the impeller. Rotation of the impeller may convey fluid through the perfusion lumen. The perfusion balloon catheter may further include a second shaft disposed in the first shaft, through the impeller, and extend distal thereof. The second shaft has proximal and distal portions and a wall. The wall has one or more apertures in the distal portion of the second shaft, and one or more apertures distal of the impeller. A perfusion lumen is disposed in the second shaft between the apertures and is in communication therewith. The impeller may be located distal of the first apertures. The impeller may be disposed under a portion of the balloon. The impeller may be made of metal, ceramic, or polymeric material. The impeller may include at least one spiral-shaped groove. The impeller may include one rib, thread, or screw. The impeller may operate like an archimedes screw. The perfusion balloon catheter may further include an external magnetic drive system adapted to provide a magnetic field to a vicinity of the magnets on the impeller. The external magnetic drive system may be powered by a source including a battery, electricity, magnetic coupling, or combination thereof. The impeller may further include a plurality of magnets disposed thereon to collectively form a continuous spiral magnet. The impeller may include a plurality of magnets disposed side-by-side to form a generally continuous magnetic thread. Each magnetic thread has an opposite magnetic polarity at its outer extremity to its adjacent magnetic thread. The impeller rotates by exposing at least one magnetic thread to successive magnetic drive magnets of the opposite polarity upon rotation of the magnetic drive system. Successive magnetic coupling between the magnetic threads and the successive magnets on the magnetic drive system causes rotation of the impeller. The perfusion balloon catheter may further include an external magnetic drive system including a magnetic surface adapted to generate a magnetic field to one or more magnets disposed on a component connected to the impeller causing a magnetic coupling and rotation of the impeller.
The invention also relates to a perfusion catheter system including a catheter having proximal and distal ends, one or more lumens, and an elongated impeller having proximal and distal ends disposed in one of the lumens. One or more magnets are disposed on the impeller or a component connected to the impeller. The impeller magnetically couples with a magnetic drive system, rotates, and moves fluid through the catheter. The catheter is disposed in a body lumen for treatment. The magnetic drive system is external to the catheter and has one or more magnets that rotate about an axis and convey a magnetic field to the one or more magnets disposed on the impeller. The impeller may move fluid in a predetermined direction when rotated.
The invention also relates to a method of actively perfusing blood through a catheter including inserting a shaft into an artery. The shaft has proximal and distal portions, a wall, one or more first and second apertures in the wall, and at least one perfusion lumen disposed therein between the first apertures and the second apertures and in communication with the first and second apertures. The perfusion lumen has at least one elongated magnetic member rotatably disposed therein. Rotating the member using an external magnetic force causes the impeller to convey fluid into one of the first or second apertures, through the perfusion lumen, and out the other of the first or second apertures upon application of a magnetic force.
The invention also relates to a perfusion catheter system including a drive system including an elongated shaft having at least one magnetic surface including one or more first magnets disposed thereon. The magnetic surface adapted to rotate and be disposed on or adjacent a body surface. The catheter is less than about 15 French in size, has proximal and distal ends, one or more lumens longitudinally disposed therein, one or more supports mounted in the lumen, and an elongated impeller having one or more second magnets disposed thereon. The drive system is adapted to rotate causing successive magnetic coupling between the first magnets and the second magnets and rotation of the impeller. The first magnets may be magnetically attracted to the second magnets of the opposite polarity and magnetically couple. The rotation of the magnetic surface may expose the second magnets to different first magnets of the opposite polarity which are disposed further along the length of the magnetic surface such that the second magnets are magnetically coupled to different first magnets as the shaft rotates causing the impeller to rotate and fluid to move in the catheter.
The invention also relates to a method of actively perfusing blood through a catheter comprising the steps of inserting a shaft into a body lumen. The shaft having proximal and distal portions, a wall, one or more first apertures in the wall, and at least one perfusion lumen disposed distal of the first apertures and being in communication therewith. The perfusion lumen has at least one impeller disposed rotatably therein. The impeller has one or more magnets disposed thereon and is adapted to rotate and convey blood through one of the first apertures and through the perfusion lumen upon application of a magnetic force thereto; applying a magnetic field to the impeller from external the body lumen; and causing magnetic coupling and rotation of the impeller using the magnetic field. The method may include using an impeller including a plurality of magnets disposed generally side-by-side to form a generally continuous magnetic thread. Each magnetic thread has an opposite magnetic polarity at its outer extremity to its adjacent magnetic thread. The method may further include the step of exposing at least one magnetic thread to successive magnetic drive magnets of the opposite polarity by rotating the magnetic drive so that successive magnetic coupling between the magnetic thread and the successive magnetic drive magnets rotates the impeller.
Still other objects and advantages of the present invention and methods of construction of the same will become readily apparent to those skilled in the art from the following detailed description, wherein only the preferred embodiments are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments and methods of construction, and its several details are capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive.